<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/640x475/54cb25654b0f2_-_polar-vortex-03-0114-de.jpg>
<http://www.popularmechanics.com/science/environment/a9897/the-science-behind-the-polar-vortex-16352023/>